Kimmeridge Rocks 4-6

The cliffs at Kimmeridge Bay in Dorset, UK, are characterised by alternating hard and soft strata. Multiple thin layers of softer shale rock are sandwiched between wide bands of harder limestone. When the shales crumble and erode out, the heavy limestone becomes unsupported, often projecting as a jagged sill from the cliff face, and dangerously prone to falling onto the beach.

In each of these photographs a projecting ledge of limestone has broken away fairly recently, perhaps in the last decade. The vertical surface is more or less flush with that of the shales above and below it in the sequence. In the last picture, Kimmeridge Rocks 6, you can see that the shales below the hard band have started to erode back once more (indicated by the dark shadow on the right cast by the overhanging limestone).

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Kimmeridge Rocks 1-3

Rock textures at Kimmeridge Bay on Dorset’s Jurassic Coast where water runs down the cliff face. Deep orange-red iron deposits on the surface of the grey limestone are revealed by recent rock falls; and granular calcium precipitation coats rock where water falls persistently.

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Cairns Botanic Gardens Flowers 2

The brightly coloured parts of the flower are in fact leaf-like bracts around the base of the flowers rather than the petals. The pink and green bracts on the upright stems shown in these pictures are typical of Heliconia psittacornis  “Sassy” and are easy to distinguish from the Heliconia mariae x pogonantha shown in the previous post which had hanging or pendant flower heads with red bracts.

In common with the bromeliad plants, heliconias often collect water in the hollows created by the bracts against the stems, These little pools become micro-habitats in which minute aquatic organisms can thrive.

Cairns Botanic Gardens

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Cairns Botanic Gardens Flowers 1

A fantastic array of tropical plants is on show at Cairns Botanic Gardens in Queensland, Australia, in both a formal garden setting and also wild as nature intended. The formal gardens include plants that are native to Australia and its tropical rainforest as well as including introduced exotic species. I think the spectacular red blooms in these photographs are a type of Heliconia in bud, most likely the giant pendant species Heliconia mariae x pogonantha which can grow to a height of 4 – 5 metres. Heliconias are native to Central and South America and also some South Pacific islands.

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Facts about Trees

This novel bronze sculpture is designed to get across the important message that trees are vital to the world we live in. It is an artwork feature by the Rhizotron and Xtrata Walkway at the Royal Botanic Gardens at Kew, London. The photographs show the overall appearance of it with a selection of the individual leaf plaques that give information relating to trees and the environment.

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Stony Ripples from Ancient Seabeds

 

There are many strange and interesting shapes and textures in the rocks on the beach at Mewslade Bay on the Gower Peninsula in South Wales. Most of them seem to be the result of weathering and erosion but these photographs show something different, unique, for that location. They appear to be preserved (fossilised if you like) ripple marks from the ancient seabed sediments of which the rocks are composed and date very approximately to about 350 million years ago. They have a distinct patterning which is very familiar from the sand and mud of present day seashores in the same area.

The rock itself is High Tor Limestone from the Carboniferous Period. Actually, It’s a bit old fashioned now to say just Carboniferous Period. Everything has changed. To be more accurate, I should say that the High Tor Limestone Formation is part of the Pembroke Limestone Group, which originated in the Visean division of the Dinantian, which in turn is part of the Mississippian sub-division of the Carboniferous Period.

What were at one time horizontal seabed surfaces have become near vertical over many millions of years of earth movements. The now-exposed surfaces of the old bedding planes are revealed in the entrances to caves at Mewslade Bay. The photographs show them encrusted with recent colonies of living acorn barnacles and occasional limpets.

Reference

Howells, M. F. (2007) Wales, British Regional Geology, British Geological Survey, Keysworth, Nottingham, UK, ISBN 978-085272584-9, pp 112 – 125.

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Red Granite 1

Reblogged from Photographic Salmagundi:

The Sausage Tree

What weird fruits! The Sausage Tree [Kigelia africana (Lam.) Benth.] is aptly named. Strangely, the flesh of these seemingly appetising fruits, whether ripened or not, is toxic to humans. The exception is that in real hard times the seeds can be roasted and eaten. Also, the fruits can be dried and fermented along with the bark to provide a flavour enhancer for traditional beers.

However, every other part of the tree can be used in some kind of herbal medicine for conditions such as digestive and respiratory complaints, and for treating infections and wounds. Currently, investigations are being carried out to determine the potential of the tree to provide source materials for use as anti-bacterial, anti-fungal, and anti-tumour agents. Extracts from the tree are already being made up into lotions that are commercially available for treating skin disorders.

The photographs in this Post were taken at Cairns Botanical Gardens in Queensland, Australia where this is an introduced tree used for ornamental purposes. The species actually hails from tropical Africa where is grows wild in riverine rainforests, wooded grassland, savannah, and forest margins. In it’s native habitat, the Sausage Tree is considered sacred and is often protected from felling.

The tree can grow from 2.5 to 18 metres high. It has beautiful red tubular flowers with yellow veins. These have a distinct smell described as strongly unpleasant or musky. The flowers only open at night and are pollinated by blossom-feeding bats and hawk moths. The fertilised flowers develop into the sausage-shaped fruits that grow to lengths of between 30 and 90 cm long and to 7.5 to 10 cm in diameter.

By coincidence, 23thorns has also written about the Sausage Tree and it’s magical properties. Do go over and have a look – it is very entertaining.

Reference

Kew Royal Botanic Gardens Website

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Natural Rock Patterns: Lithologic Series 1-12

Patterns of iron-stained calcite deposited on the surface of quarried limestone on the Isle of Portland – which is part of the UK’s Jurassic Coast.

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Septarian Nodules at Ringstead

What is a septarian nodule? Well, basically, it is a big boulder containing a three dimensional jig-saw of smaller angular pieces of the same rock – and all the pieces are bound together with white crystalline calcite. I can’t do better than to quote the definition given in The Oxford Dictionary of Earth Science:

A concretion, roughly spheroidal in shape, usually of clay ironstone, and characterised by an internal structure of angular blocks separated by radiating mineral-filled blocks. The mineral filling the cracks is usually calcite. The structure results from the formation of a hard exterior to the nodule due to the development of an aluminous gell on the exterior, followed by dehydration of the colloidal mass in the interior, leading to cracking and subsequent infilling of the radiating pattern of cracks.

The British Regional Geology Series for the area indicates that the Ringstead Waxy Clays, which are virtually at the top of the Corallian Beds of the Upper Jurassic strata, comprise about 5 metres of clay with thin seams of clay ironstone that are nodular in places. It seems very possible that the septarian nodules are from this source. The Ringstead Waxy Clay is also the deposit in which numerous fossil oysters, Deltoideum (Liostrea) delta, are found [mentioned elsewhere in Jessica's Nature Blog and also on the sister site Oysters etc.]

References

Oxford Dictionary of Earth Sciences, Edited by Michael Allaby, Oxford University Press, first published 1990, third edition 2008, ISBN 978-0-19-921194-4

The Hampshire Basin and adjoining areas,  R. V. Melville and E. C. Freshney (1982),  British Regional Geology Series, Fourth Edition,  Institute of Geological Sciences, HMSO, ISBN 0-11-884203-x.

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